In U.S. Pat. No. 4,660,508 of the present inventor is disclosed a feeder for animals, of the type for feeding dry feed in particulate form, which includes a substantially horizontal shelf beneath a hopper so that the feed from the hopper is discharged onto the shelf and the amount of feed discharged can be controlled by small adjustment of the height of a lowermost edge of the hopper relative to the shelf. The shelf is located above a trough with a base and a front wall of the trough over which the animal can reach to take feed from the shelf and any feed which is moved from the shelf to the trough by the animal. Beneath the shelf is a water pipe extending along the feeder with nozzles to be operated by the pigs which discharge downwardly into the trough.
This type of feeder has become very successful and is widely known as a wet/dry feeder in view of the fact that the animal can take dry feed from the shelf of the feeder or can apply water into feed discharged into the trough to take the feed in the trough in wet condition.
Feeders of this type are generally double sided that is the feeder has two sides each of which can be accessed by a different set of animals so that generally the feeder is placed in a fence line to supply feed to animals in two separate pens. The feeder may however simply be placed in a pen and accessed from both sides. Of course a double sided feeder is cheaper to make than two single sided feeders.
In U.S. Pat. No. 5,640,926 of the present inventor issued Jun. 24, 1997 is disclosed a feeder of this type in which the height of the shelf from the trough is adjustable so as to accommodate a change in size of the animals from a smaller size up to a larger size as the animals grow. This feeder is commonly used to raise pigs from weanling up to a larger size such as “wean to finish”. Thus the self is moved to a lowermost position for the very small weanlings and then raised as the animals grow. The difficulty with using a one-size feeder is that it must be sized to accommodate the largest size the animals reach and hence the feeder is too large for the weanlings. The weanlings can thus climb into the trough and can try to get under the shelf from one side to the other. This is unsuitable and potentially dangerous for the animals in that they can get stuck. It is known therefore to weld on the water pipe downwardly extending bars which reach to a position close to the trough so as to act as a barrier along the trough underneath the water pipe. Spaces are provided in the structure at the water nipples.